1. Field of the Invention
The present invention relates to high density recording media such as optical discs, and in particular, blu-ray read-only discs.
2. Description of the Related Art
Optical discs that are capable of storing large amounts of high-quality video and audio data, have been available on the market. The digital versatile disc (DVD) is one example of such an optical disc. Recently, DVD players and DVD recorders have been available on the market and have become one of the most popular consumer electronic products.
Auxiliary presentation data such as subtitle information that is to be displayed on screen during playback of a DVD title (e.g., a movie) is, in general, recorded on the DVD as bitmap-formatted image data. During playback of main audio/video data recorded on the digital versatile disc, the auxiliary presentation information is read out from the digital versatile disc and output to an external device such as a TV set after a series of signal processing steps so that the auxiliary presentation data is displayed on the screen of the external device. With a DVD player, a user can choose and watch a desired subtitle on a TV set during reproduction of the DVD title.
Recently, the standardization of new higher density optical discs than DVD, for example blu-ray read-only disc (BD-ROM) has been under development. Standard specifications and methods of providing a great level of flexibility in managing and displaying auxiliary presentation data, which are recorded on the optical disc or supplied from a content provider server through the Internet, have not yet been established.